Method and device for the metered dispensing of a medium

ABSTRACT

A method for metered dispensing of a medium from a container, a dosing pipette (P 1 P 2 ) for removing an exactly predetermined amount of the medium to be inserted into the container, wherein the predetermined amount is adjusted on the dosing pipette (P 1 P 2 ) prior to removal.

BACKGROUND OF THE INVENTION

The invention relates to a method for the metered dispensing of a mediumfrom a container by means of a dosing pipette for removing a preciselypredetermined amount of the medium, wherein the predetermined amount isset on the dosing pipette prior to removal.

In many cases in daily life or also in industrial applications, amedium, in particular liquid, has to be removed from a container. Thisis also particularly true in the field of medicine. Generally speaking,a pipette is known for this, said pipette being inserted into thecontainer and the medium being sucked into a small tube by pressing andreleasing a rubber element. In this case, it is not possible to meterthe medium to be removed.

WO2004/054720, for example, makes known a metering device for sucking upand dispensing a free-flowing medium from a container, said devicehaving an inlet and an outlet, and inlet and outlet are disposedseparated from one another and a metering and displacement chamber isprovided between them. Both inlet and outlet are sealable. In this case,however, said metering device is a permanent component of the containeritself and cannot be handled separately from said container.

WO 00/18453 also makes known a metering device. However, along with theremoval device said device also includes a container and it is onlypossible to use said devices in combination with one another. A wheelthat is situated above the container closure can be rotated to set thedesired amount.

It is an object of the present invention to enable a metered removal ofa medium from a container and the separate handling of said removaldevice from the container. In addition, the long-term use of the deviceis to be improved and faulty dosings avoided.

SUMMARY OF THE INVENTION

The object is achieved in that an opening in the container or acontainer closure is sealed with a removable sealing plug prior to theinsertion of the dosing pipette by the sealing plug being inserted intothe container closure from the inside and through the insertion of thedosing pipette being ejected into the interior of the container.

This means that by using a pipette that is insertable into thecontainer, the amount of the medium removed corresponds precisely to thewishes of the user, who can also alter the amount removed, if desired.

If the container is a sealed bag, for example, the dosing pipettedirectly penetrates said bag. As a rule, however, the container shouldbe a bottle or similar that is provided with a container closure. Inthis case, it may be advisable to provide the container closure with anopening into which the pipette can be inserted.

Prior to the first insertion of the dosing pipette, said opening shouldbe provided with a sealing plug so that the medium present in thecontainer is not contaminated. By the dosing pipette being inserted,said sealing plug is moved out of its sealing position, remaining, inone exemplary embodiment of the invention, connected to the containerclosure by means of a securing ring. In this case, the sealing plug canbe moved back into the closed position if the container closure is to beused for another bottle.

In another exemplary embodiment of the invention, the sealing plug isinserted into the opening in a detachable manner. It is expelled intothe interior of the container by the dosing pipette. If it is ofsufficient weight, said sealing plug can then also be used as a mixingelement for the medium, if the container has to be shaken before use,for example.

A dosing pipette according to the invention comprises only threeelements that are preferably produced from plastics material. The firstis a metering housing, into which a plunger, the second, is inserted,which, in its turn, is limited in its stroke movement relative to themetering housing by the third element, namely a cam.

The metering housing is preferably a small elongate, cylindrical tubewhich, where applicable, tapers downwards and there surrounds an intakeopening. Towards the top, said tube is somewhat widened and, in anexemplary embodiment, accommodates a stop ring, from which a camprojects inwards into the clearance of an axial recess of the tube, inwhich axial recess the plunger is also guided. Said stop ring can beinserted into a corresponding annular recess in the widening and isengaged over towards the top by a flanged edge of the metering housing.Other possibilities for securing the stop ring in the housing are alsoconceivable here.

In another exemplary embodiment, the cam is a separate element that isinserted into the metering housing into a radial guide. Additional guiderails to facilitate the insertion of the cam can also be provided insaid radial recess. In addition, a web is situated in the radial recess,said web being traversed by the cam during insertion and snapping-inbehind the cam to prevent the cam sliding out of the recess.

The plunger, in its turn, has a neck region with a smaller diameter thanthat of a plunger outer surface. Said diameter is selected such that theneck can slide past the cam when the plunger is rotated. Said diameterthen continues in grooves which are integrally formed in the plungerouter surface. I.e. the cam can slide in said grooves but at the sametime forms an anti-twist protection here such that when the cam engagesthe grooves, only an axial movement of the plunger relative to themetering housing is possible. So that it is easier for the cam to findthe groove associated with it, said groove has a conical groove inlet.

A plurality of grooves is integrally formed in the plunger outer surfacedistributed about the axis. Said grooves have different lengths so thatthey also allow for a different stroke of the plunger relative to themetering housing. Said stroke then determines the metering amount thatis sucked into a metering space. Said metering space is formed by an endjournal of the plunger, an annular lip of the plunger surrounding saidend journal and the metering housing and expands during the axialmovement of the plunger relative to the metering housing.

The setting of the metering amount is effected by rotating the plungerabout the axis as soon as the cam is in the region of the neck of theplunger. To recognize the dose, in this case, markings are provided on aflange of the metering housing, it being possible to determine saidmarkings with an indicator on the plunger. For the user this representsvery simple handling, preventing faulty dosing.

The entire structure of the dosing pipette is very sturdy, simple andinexpensive to produce. The entire pipette and the materials used in itsproduction are consumer-friendly in accordance with the guidelines forthe pharmaceutical industry and permit clean handling.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, features and details of the invention proceed fromthe following description of preferred exemplary embodiments and by wayof the drawing; in which

FIG. 1 shows a longitudinal section through a dosing pipette accordingto the invention;

FIG. 2 shows a top view of the dosing pipette in FIG. 1;

FIG. 3 shows an outline of a plunger of the dosing pipette in FIG. 1;

FIG. 4 shows a cross section through the plunger in FIG. 3 along theline IV-IV;

FIG. 5 shows an enlarged cross section through the dosing pipette inFIG. 1 along the line V-V;

FIG. 6 shows a longitudinal section through another exemplary embodimentof a dosing pipette;

FIG. 7 shows an exploded representation of an enlarged part region ofthe dosing pipette in FIG. 6;

FIG. 8 shows a schematically represented cross section through thedosing pipette in the part region in FIG. 7;

FIG. 9 shows a longitudinal section through a container closureaccording to the invention;

FIG. 10 shows a longitudinal section through the container closure inFIG. 9 with the dosing pipette inserted in the position of use;

FIG. 11 shows a longitudinal section through another exemplaryembodiment of a container closure with the dosing pipette beinginserted.

DETAILED DESCRIPTION

According to FIG. 1, a dosing pipette P₁ has a metering housing 1, intowhich a plunger 2 is inserted. The plunger 2 sits in an axial recess 3of the metering housing 1 and is rotatable in said axial recess 3 anddisplaceable along an axis A.

According to FIGS. 3 and 4, the plunger 2 has a plunger outer surface 4,in which a plurality of grooves 5.1 to 5.4 is integrally formed. Each ofsaid grooves 5.1 to 5.4 has a groove inlet 6 that is conical.

The plunger outer surface 4 forms a step 7 towards the top, a neck 8connecting to said step, a diameter d of the neck 8 being smaller than adiameter d₁ of the plunger 2 in the region of the plunger outer surface4. A disc 9 with a lug 10 (see FIG. 2) is placed onto said neck 8. Saiddisc 9 can be in the form of a head in an arbitrary manner and can beplaced on the neck 8 or integrally formed with said neck.

Towards the bottom an annular lip 11 connects to the plunger outersurface 4, said annular lip widening outwards in a conical manner. In sodoing it partially surrounds an end journal 12.

The metering housing 1 tapers towards the bottom and there surrounds anintake opening 13. In the closed position, the plunger 2 sits with itsend journal 12 in said intake opening 13. The annular lip 11 abutssealingly against the axial recess 3 and thus forms, together with themetering housing 1 and the end journal 12, a metering space 14, whichexpands as the plunger 2 moves along the axis A.

Numerous possibilities are conceivable for the development of the regionof the intake opening 13 depending on what the dosing pipette is to beused for. The development for vaginal application can be different tothe development for rectal application. If the dosing pipette isconceived as an ointment applicator, spherical geometry can be used sothat no injuries are caused. In addition, for example, the end journal12 can also be provided with an external thread so that it can bescrew-connected into a corresponding internal thread of a container. Anexternal thread of this type can also be used, for example, toscrew-connect a spherical region which, as mentioned above, avoidsinjuries. It is also conceivable to attach a sleeve section with aninternal thread that then surrounds the end journal 12, the internalthread being capable of being screw-connected to an external thread of atube. The end journal 12 then engages the tube opening. Manypossibilities are conceivable in this case and are to be included in thepresent invention.

At the oppositely situated end a stop ring 16 is engaged in a housingwidening 15 of the metering housing 1 and is retained by a flanged edge17. A cam 18 projects from said stop ring 16, as shown in FIG. 5, intothe clearance of the axial recess 3 of the metering housing 1, said cam,in the position of use, engaging one of the grooves 5.1 to 5.4 of theplunger 2.

Markings 20, which contain information concerning the metering amount,are situated on a housing flange 19. Said metering amount depends on astroke h that is indicated in FIG. 6.

The method of operation of the present invention is also discussed inparticular by way of FIGS. 9 to 11:

A container (not shown in any more detail), for example for a medicalliquid, is sealed by a container closure 21. This can be a screw-typeclosure for example. An insert 22, which is preferably produced from asofter plastics material than the container closure 21, is situated inthe container closure 21. An opening 23, which is preferably providedwith capillaries 24, is integrally formed in said insert 22. A closureplug 25, which is connected to the insert 22 in a captive manner bymeans of a securing ring 26, sits in the opening 23.

To remove a predetermined amount of medium from the container, thedosing pipette P₁, as shown in FIG. 10, penetrates the opening 23,beforehand or afterwards the lug 10 of the plunger 2 having been set tothe desired marking determining the metering volume. When the dosingpipette P₁ is inserted into the opening 23, the sealing plug 25 isejected and remains suspended in the interior of the container closure21, as shown in FIG. 10.

The container together with the container closure and the dosing pipetteis then turned upside down and the plunger 2 is moved in the directionof the axis A in the axial recess 3, the medium present in the containerthereby being sucked into the metering space 14 in a desired meteringvolume. During the movement of the plunger 2, the cam 18 moves along thepredetermined groove 5.1 to 5.4 until it abuts against the bottom 27 ofa groove. This limits its stroke h, which at the same time means thatthe desired amount of medium is situated in the metering space 14.

The pipette is then pulled out of the opening 23 and, to discharge themedium from the metering space 14, the plunger 2 is moved in theopposite direction along the axis A, the volume of the metering space 14thereby being reduced. In this case, the annular lip 11 seals off themetering space 14 so that the entire medium can be discharged throughthe intake opening 13.

Towards the end of this movement, the end journal 12 engages the intakeopening 13 and seals the same hermetically relative to the outside sothat bacterial contamination in the system is excluded.

If a different metering amount is desired, the plunger 2 is rotatedabout the axis A and the lug 10 is set to the desired marking 20. Thismeans that the cam 18 then runs down a different groove 5.1 to 5.4 thathas a different length and corresponds to the desired metering volume.

FIG. 11 shows that it is also possible for a sealing plug 25.1 to bedisposed in a detachable manner in the opening 23. When the dosingpipette P₁ pierces the opening 23 in this case, the sealing plug 25.1falls into the interior of the container, as shown by the dot dash line,and can be used there to mix up the medium when the container is shaken.

A dosing pipette P₂, as shown in FIGS. 6 to 8, differs from the dosingpipette P₁ in that the cam is not part of a stop ring, but is a separateelement. Said cam 18.1 is inserted laterally in a radial manner into arecess 28 in a metering housing 1.1, it being possible for saidinserting to be supported by corresponding guide rails (not shown). Inthis case, a web 29 is formed in the recess 28 for the cam 18.1, saidweb, in the end position of the cam 18.1 where said cam, as shown inFIG. 6, abuts against the metering housing 1.1 with a stop 30, engagesbehind the cam 18.1. In this end position the cam 18.1 sits in therecess such that its end face 31 abuts against the neck of the plunger 3and can thus slide into the grooves 5.1 to 5.4.

The invention claimed is:
 1. A dosing pipette for the metered dispensingof a medium from a container comprising a metering housing, a plungerseated in the housing and axially displaceable therein in a limitedmanner by rotation of the plunger by a stroke limitation device, thestroke limitation device comprises an interaction between a camassociated with the metering housing and a plurality of grooves ofdifferent lengths which are formed axially in an outer surface of theplunger, wherein the cam engages one of the grooves on the outer surfaceof the plunger thereby (1) determining a volume of the medium to bedispensed and, at the same time, (2) providing anti-twist protection asa result of the interaction between the cam and the associated groove.2. The dosing pipette as claimed in claim 1, wherein at least one of theplurality of grooves has a groove inlet.
 3. The dosing pipette asclaimed in claim 1, wherein the cam is part of a stop ring which isinserted into the metering housing.
 4. The dosing pipette as claimed inclaim 3, wherein the stop ring is flanged into the metering housing. 5.The dosing pipette as claimed in claim 1, wherein the cam is insertedinto a recess provided radially in the metering housing and projectsinto a clearance of an axial recess of the metering housing.
 6. Thedosing pipette as claimed in claim 5, wherein the cam is clipped intothe recess.
 7. The dosing pipette as claimed in claim 5, wherein theplunger is supported against the metering housing by an annular lip. 8.The dosing pipette as claimed in claim 5, wherein, in the closedposition, the plunger seals an intake opening in the metering housing byan end journal.
 9. The dosing pipette as claimed in claim 8, wherein theend journal is conical.
 10. The dosing pipette as claimed in claim 5,wherein information for metering volume is located on an upper housingflange of the metering housing, said information interacting with a lugon the plunger.
 11. A dosing device for metered dispensing of a medium,comprising: a metering housing for receiving a volume of the medium tobe dispensed; a plunger which is axially displaceable in the meteringhousing in a limited manner over a stroke of movement, the plungerhaving a plurality of channels of different lengths extending axially ina periphery of the plunger, and a stroke limitation device comprising aprojection associated with the metering housing which is configured toproject into and interact with a selected one of the plurality ofchannels formed in the periphery of the plunger, wherein the plunger isconfigured for rotation relative to the metering housing to select oneof the plurality of channels, such that the projection projects into andinteracts with the selected one of the channels to determine a length ofthe stroke of movement of the plunger and thereby also the volume of themedium to be dispensed, and to provide anti-twist protection.
 12. Thedosing device as claimed in claim 11, wherein the plunger is axiallydisplaceable in the metering housing over the stroke of movement from aclosed position, in which the plunger seals an intake opening at an endof the metering housing, such that during the movement of the plunger,the projection moves along the selected one of the channels until itabuts against an end of that channel.
 13. The dosing device as claimedin claim 12, wherein the plunger seals the intake opening at the end ofthe metering housing in the closed position via a conical end journal.14. The dosing device as claimed in claim 11, wherein the meteringhousing comprises an elongate, generally cylindrical tube having anintake opening at an end thereof for intake of the volume of the mediumto be dispensed.
 15. The dosing device as claimed in claim 11, whereineach of the plurality of channels has a channel inlet for receiving theprojection.
 16. The dosing device as claimed in claim 11, wherein theprojection is provided on a stop ring mounted on the metering housing.17. The dosing device as claimed in claim 16, wherein the stop ringforms a flange at an end region of the metering housing.
 18. The dosingdevice as claimed in claim 11, wherein the projection projects into anaxial recess of the metering housing within which the plunger is axiallydisplaceable.
 19. The dosing device as claimed in claim 18, wherein theplunger is supported against and seals against the axial recess of themetering housing via an annular lip.
 20. The dosing device as claimed inclaim 11, wherein markings that provide information concerning ametering amount are situated on a housing flange of the meteringhousing.